Control mechanism for presses



9 1936- K. F. -WAGNER 2,063,644

- CONTROL MECHANISM FOR PRESSES Fild Aug. 51, 1951 INVENTOR- fi'avrzFrieczridlu mr a I t 1 I t -IORNEYS Patented Dec. 8, 1936 UNITED STATESPATENT OFFICE signor, by mesne assignments, to Magnesium DevelopmentCorporation, Newark, N. J., a corporation of Delaware Application August31, 1931, Serial No. 560,431 In Germany September 15, 1930 4 Claims.

This invention relates generally to control mechanisms and particularlyto control mechanisms for automatically-operated hydraulic or pneumaticpresses, such as die-casting machines and the like.

Control mechanisms for automatically-operated machines of the type abovereferred to usually comprise a shaft provided with a series of camswhich actuate the valvesfor admitting and releasing the pressure to andfrom various parts 'of the machines to control their normal cycle ofoperations. It is often necessary, in the operation of automaticpresses, to change from automatic to hand operation. This isparticularly desirable when the working conditions attendant to a newobject, or work-piece, are to be ascertained, or where only a smallnumber of a particular object or work-piece are to be made.

In present cam-controlled presses the cams, which actuate the variousvalves in the opera tion of such mechanisms, are usually arranged on asingle shaft, each cam serving to open a valve by means of a suitabletappet, whereas the closing of the valves is usually effected by meansof springs. Valve mechanisms involving springs are not always reliable,and in the present invention the inherent disadvantages of suchmechanisms have been eliminated.

The main object of the present invention is to provide an automaticcontrol mechanism for hydraulic or pneumatic presses which is simple inconstruction and which may be readily' changed over from automatic tohand or manual operation. Other objects will be apparent onconsideration of the following description when taken in connection withthe attached drawing in which: 1

Fig. 1 represents, in diagrammatic form, a front view of a, valvecontrol mechanism comprising a pair of cams mounted upon a pair of camshafts and means for automatically operating said valves;

Fig. 2 represents a view similar to that shown in Fig. 1 in which themechanism is adapted to be manually or hand operated;

Fig. 3 represents, in diagrammatic form, a section taken on the lineIII-III of Fig. 1;

Fig. 4 is a fragmentary view, to enlarged scale, in part section andwith parts broken away illustrating the interconnection between thetappets c and c with the bell-crank lever d.

In order to insure the positive actuation of cam-operated valves in bothdirections, without unduly extending the length of the cam shaft, thevalves in the present invention are arranged open position, releasespressure.

in pairs, one valve in each pair serving to admit pressure and the othervalve serving to release pressure. Positive actuation of the valves isprovided for in the form of a bell-crank lever or the like to which thetappets of the respective valves in each pair are connected. Cams foractuating the valves in controlling the various operations of themachine are suitably mounted adjacent each other and in the same planeon two separate shafts and cooperate with the bell-crank lever tosimultaneously open and close the valves in each pair. To insure propercooperation of the cam shafts, and the correct relative positions of thecams mounted thereon, the two cam shafts are connected together by meansof a suitable gear train or by cog-wheels.

Both of the cam shafts according to this invention are supported in sucha manner that they may be moved apart or separated to a moderate extentto remove the cams from their cooperating positions with respect to theaforementioned bellcrank lever. When separated the cams are preventedfrom actuating the valves, which may then be manually or hand operated.Preferably the separation of the two cam shafts is limited to an extentwhich permits the gear train or cog-wheels to remain in loose mesh,which condition retains the accurateregistry of the cams when themechanism is returned to automatic control.

Referring particularly to the drawing a represents a single distributor,a number of which are usually combined to form a. unit disposed in adirection parallel to the cam shafts. Each distributor comprises a pairof valves b and b respectively, one of which, in its open position,admits pressure, whereas the other valve, in its Each pair of valves isactuated by means of a bell-crank lever d composed of spaced plates(Fig. 3) provided with a free arm is, which bell crank is adapted toreciprocate the valve tappets c and a, re-

formed integral with the tappets c and 0 respectively. The free arm ofthe bell-crank is provided with a cam follower or roller j which,

. during automatic operation, is engaged by the oppositely-disposed camsn and n keyed to tubular shafts or sleeves m and m rotatably mountedupon the eccentric portions 10 and p of the parallel shafts 1' and 1'.The shafts 1' and r are suitably journalled and are adapted to besimultaneously rotated, in opposite directions, through the medium ofgears or cogwheels q and q*, or handles 2: and :r", fixed to the shaftsr and 1*. This construction permits the eccentric portions p and p ofthe parallel shafts to be separated a moderate distance from theposition shown in Fig. 1 to that shown in Fig. 2, in which latterposition the cams are removed from engagement with the follower f andthe valves may be operated manually.

Preferably formed integrally with 'thecams n and n are gears orcog-wheels g and g, which, as shown in Fig. 3, are not in the same planebut are oifset'with respect to each other and mesh with an idler pinionor cog-wheel s mounted upon the shaft t in any suitable manner. It willbe readily understood that the gears g g and s will remain in meshwhether the cams n and n are in contact with the cam follower f, asshown in- Fig. 1, or removedtherefrom, as shown in Fig. 2, the looseengagement of the gear teeth, in the position shown in Fig. 2, beingsufficient to retain the cams in proper relative position with respectto each other. This arrangement of gears permits a means for driving thecontrol mechanism, as it is possible to drive the shaft t in anysuitable manner. Furthermore, the shaft tmay be driven at any suitablepredetermined speed in accordance with the desired speed of operation ofthe control system. As shown in the drawing, the contour of the earns11. and n is identical and the cams are provided with relatively largecrests l and l and relatively small crests v and v The crests v and vare brought into position in engagement with the follower f once duringeach revolution of the cams n and n", which rotate in the directionindicated by the arrows in Fig. 1. In the position shown in Fig. 1 thefree arm 70 of the bell-crank lever d is brought into a verticalposition and both of the valves b and b are closed.

Continued rotation of the cams from the positions shown in Fig. 1oscillates the bell-crank lever d whereby valve 17 is opened or raisedand valve b remains closed during the first 180 of rotation, whereasduring the second half of the cycle valve 12 is opened and valve 2) isclosed. The crests v and 12 therefore insure a definite dwell duringeach complete revolution of the cams n and n, at which time both valvesare in their closed position.

In order to change from automatic to manual or hand control it is onlynecessary to rotate the shafts r and 1' through 180 in any suitablemanner by means of the handles 2: and x or the gears q and q whichaction separates the cams n and n a definite distance, in view of theireccentric mounting, and permits manual control of the valves through themedium of thegrip h attached to the bell-crank lever d.

I claim:

1. In a device for controlling the operation of automatic fluid-operatedpresses, a pressure distributor comprising a valve for admittingpressureand a valve for releasing pressure, oscillatory means forpositively actuating said valves, a pair of shafts journalled a definitedistance apart, said shafts having eccentric portions formed thereon, acam rotatably mounted on each of said eccentric portions, means forrotating said shafts to change the relative positions of said eccentricportions and to thereby separate said cams, and means associated withsaid cams for maintaining definite relationship therebetween for allpositions thereof, said cams being adapted to impart an oscillatorymovement to said valveactuating means.

2. In a device for controlling the operation of automatic fluid-operatedpresses, a pressure distributor comprising a valve for admittingpressure and a valve for releasing pressure, oscillatory means forpositively actuating said valves, a pair of parallel shafts journalled adefinite distance apart, said shafts havingeccentric portions formedthereon, a cam rotatably journalled on each of said eccentric portions,means for rotating said shafts to change the relative positions of saideccentric portions and to thereby separate said cams, and gearsassociated with said cams for driving the same at predetermined equalspeed and for maintaining definite relationship therebetween for allpositions thereof, said cams being adapted to impart an oscillatorymovement to said valve-actuating means on rotation having eccentricportions formed thereon, a cam rotatably journalled on each of saideccentric portions, means associated with said shafts for rotating thesame to change the relative positions of said eccentric portions and tothereby separate said cams, and means mounted on said eccentric portionsin association with said cams for driving the same at predeterminedequal speed, said last-mentioned means being adapted to maintaindefinite relationship between said cams for all positions thereof, saidcams being adapted, on rotation, to impart an oscillatory movement tosaid bell-crank lever.

4. In a device for controlling the operation of automatic fluid-operatedpresses, a pressure distributor comprising a valve for admittingpressure and a valve for releasing pressure, a pair of parallel shaftsjournalled a definite distance apart, said shafts having eccentricportions formed thereon, a tubular shaft rotatably mounted on each ofsaid eccentric portions and having a cam secured to each tubular shaft,a bell-crank lever pivotally mounted and having a depending free armdisposed between and adapted to cooperate with said cams, meansassociated with said shafts for rotating the same to change the relativepositions of the eccentric portions and to thereby separate said camsand remove the same from cooperating position with respect to saidbell-crank lever, tappets associated with said valves and bell-cranklever, and means for driving said tubular shafts at a predeterminedequal speed whereby said bell-crank lever is oscillated and saidoscillatory movement is imparted to said tappets to positively actuatesaid valves, said cams in their separated position permitting actuationof the valves through manual operation of said bell-crank lever.

KARL FRIEDRICH WAGNER.

